Objectives Determine whether female marmosets that ovulate while housed in the natal family differ behaviorally and socially from those that remain reproductively suppressed. Although female common marmosets typically do not breed while housed with their natal families, up to half ovulate at least once while housed with the intact natal family, and a similar proportion conceive if an unrelated adult male is present in the group. In this study, we investigated the behavioral and social correlates of escape from ovulation suppression by daughters housed in intact natal families or in families in which the father had been replaced by an unrelated adult male. Focal-animal behavioral data were collected over a 2-week period from daughters that were (N=7) or were not (N=10) undergoing ovulatory cycles while housed with the natal family and from daughters that were (N=5) or were not (N=3) cycling in families containing an unrelated male. In addition, four cyclic and six acyclic females housed in intact natal families underwent simulated dispersal tests. Cyclic and acyclic daughters in intact natal families did not engage in sexual interactions with the father and showed few differences from one another in their social interactions with the parents. Moreover, cyclic and acyclic daughters did not differ in their willingness to "disperse" from the family and investigate an unfamiliar family. However, daughters that underwent ovarian cycles in the presence of an unrelated adult male showed numerous behavioral differences from those in intact natal families, including frequent courtship and sexual behaviors with the male, reduced affiliative interactions with the mother, and elevated frequencies of aggressive display behavior. In addition, these females were less likely to behave submissively towards either the mother or the adult male. These findings suggest that both suppression of ovulation and inhibition of sexual behavior normally contribute to reproductive failure in female marmosets living with their natal families, and that the two components of suppression may become dissociated under specific social conditions. Key words ovulation suppression, dominance, social relationships, sexual behavior, novel male effect